I do apologise if I have offended you. If you are standing up for someone else please let me know who I offended so I can apologise to them.
Trying to describe an algorithm for curve extension by elevation without a mathematics degree is not simple just using English language, and neither is trying to describe inflate deflate algorithm for plane manipulation.
What you call obfuscation is language difficulty.
In tech drawing a tangent is a smooth circumference section that connects two circles perfectly. When considering cylinder and line thickness this is very difficult to describe. As surface should consider length of cylinder line thickness to be cylinders themselves.

You haven’t offended me other than that you don’t take the time and effort to make some decent sketches in which you clarify your words.
Right from the beginning i’m still not covinced that I (we) are dealing with “intelligent trolling”, and you are having a laugh at us. What I did, the simple models, was fun to do and may or may not help you. But it’s up to you (decent sketches) whether I can do anything with your requests.

Again I thank you Wo3Dan I did want to keep the design secret and learn how to design myself.
But in order to explain the algorithms missing is very difficult without knowing the program language.
I did rush the sketches as I felt pressured to respond quickly.
I have been thinking of milling and 3d print tool heads and the orientation commands to produce the effect as well as trying to ascertain how to get a graphics package to plot in a similar fashion for integration and speed up procedures.
I do understand we come from different skill sets.
If I wanted you to do the design for me I would have preferred to be able to think of you as a staff member and share any proceeds with you, but I do not have a business license.
I do not mind too much about giving the design away as I do get paid benefits and it does make me feel like I am contributing for what I receive.

The outer bearing will not need many balls in the ball race but they will have to have location retainment. To reduce friction. Blade size is limited for max aero effect by depth (or height) of bearing and fan centre, this also reduces drag effect loading on motor.
My attempts at free hand drawing the heatsink is very difficult in 3d. As the orientation angle for the root curve needs to be precise.
I can cut a template for the root curve and try in 2d to portray but that is what the software should be for.
I guess I can go without transport, insurance, social life, clothing and reduce food intake for 2 or three years and get a proper course.

… I did want to keep the design secret and learn how to design myself. …

You still can learn to design it yourself if you are willing to listen to suggestions people make in this thread. And I for sure, am not after your secret design.

alan50:

… But in order to explain the algorithms missing is very difficult without knowing the program language. …

What language are you talking about? You can apply SketchUp as is or with the help of some already written plugins. That’s what most of us do.

alan50:

I do understand we come from different skill sets.

You may be assuming wrong. I’m perfectly capable of understanding mechanical engineering. That’s where I origionaly come from.

alan50:

… to be able to think of you as a staff member …

I’m not a staff member of any company. I’m as free as a man can be.

alan50:

… but I do not have a business license. …

Well, if you intend to, at some point, make money out of your project you’ll need a license for SketchUp Pro.

I think you make things way too difficult for you (and us!). Chop the design into understandable chunks and sketch them. (a shaft and what the blade looks like at that side in top view and in side view. Then another sketch about the other (outer) side of the blade. etc.
Up until now I see only one sketch that doesn’t reveal too much.

“What language are you talking about? You can apply SketchUp as is or with the help of some already written plugins. That’s what most of us do.”
I wrote in feature requests due to not having been advised about plugins.
I am pleased that there has been interest in this thread, but I was expecting to speak to someone who can make features for the software.
The free version, even on a trial should be a good version to entice the user to want to purchase a product that is off the shelf workable.
The features that I have attempted to describe would be very useful.
I am glad however that yourself and others have looked and helped to show the difficulties.

Thank you box your input is very helpful.
The features i require are:
Parallel lines - perpendicular to surface.
Elevated curve that maintain 2d curve perspective.
Curved area fill.
Geometry matching curvitude.
Plane convex and concave variable would be an added bonus of elevated curve algorithm.
Sorry if this breakdown of request is too detailed for you !

There are many ways to make screw threads in SketchUp. Here is one more using the Spirix plugin …
One of the aspects of SketchUp that makes circular objects such an issue in 3D printing is the use of line segments to approximate an arc. This is glossed over by the visual smoothing functions that make even relatively crude circles look smooth. While this is fine for visual aids and drawings, any circular arcs that will be 3D printed will need many more line segments than usual. However, this is …

Thank you Mike that is useful to the variable output helix propulsion featured earlier but is not related to the feature requests.
For concentric perpendicular parallel surface lines line follow is the option but this planar orientation is an issue even with that.
Think of where a parallel helix would be just by wanting a parallel.

When using push to create cylinder the program does not plot centre line right through as far as I am aware this would be where i would attempt to get perpendiculation from surface radially. This is how I would align the root curve to surface, previously mentioned, prior to extending each root curve geometry to cylinder surface(these lines would be blade centre line parallels.)
Planar orientation would be for blade pitch angle.
Move morphs, is there rotation ?
The variation in length of root curve to flat along blade is particularly difficult to plot individual geometries for material fill selection. And those geometrical flats do not tell a machine how to create smooth graduation.

In truth I have many rough sketches of things I would prefer to see in the market place.
I have enjoyed this thread.
I do hope others have enjoyed it too.
Wo3Dan you are welcome to produce a drawing for the fan. I can give more details of other projects preferably by private email but I am having quite serious email problems. The mail I have tried to archive is not there and some emails I deleted are. I am not sure why this is the case but I have sent feedback to windows about it.